Looks like stonecrop to me

Proper name is Sedum album. There are dozens of slightly different forms of this so which one needs a real expert to distinguish.

Thanks, both! I guessed it was a sedum - pretty, isn't it? does it look after itself? - it's growing in several dry-stone type walls/rock garden areas here...

Native to the area so yes it pretty much looks after itself.

If it likes your garden you will soon be yanking it out by the bucket full...

Oh, dear, MG! still it'll make a change from pursuing bracken fronds and hazel trees...

and definitely easier to weed out MJ

yes, indeedy! every photo I take of my overgrown garden has the Dreaded Hazel as a backdrop, at present!